My dislike of Transistors...

[Hippogriff]

Hi all,

I have a circuit where I use 3 x BC337 transistors to drive / switch an RGB LED strip from 12v... I find transistors very finicky to work with, with their stupid little legs and potential for getting too hot with my inept soldering, and, when soldering them, they're always the pieces that I dread working on... resistors are fine, PICs are fine, but the transistors are a pain.

Obviously I should work around this with practice and grow to love them. However, what I wanted to ask - is there anything that can replace my three transistors in my circuit, like - for example - an IC? Is there an IC that is, basically, able to take on the part of several transistors and provide 12v to an RGB LED strip? A transistor understudy, waiting in the wings?

I would much prefer to use a small, cheap, IC in place of these transistors, but - again - I just don't know what I don't know until I ask. Would such an IC (if the concept even exists) need to be programmed, or would the transistor 'functionality' already be in it? Does the question even make sense?

I can scribble a diagram if need be...

 

[Pommie]

Just calm down. Trannies are good guys. Give them a chance and you will grow to love them.

Mike.

 

[Hippogriff]

I don't mind trannies - I'm a very live-and-let-live kinda guy - but transistors I can't stand.

 

[BrownOut]

I don't mind trannies - I'm a very live-and-let-live kinda guy - but transistors I can't stand.

HAHAHAHA! Now that started my day out with a laugh!

 

[Vizier87]

I would much prefer to use a small, cheap, IC in place of these transistors, but - again - I just don't know what I don't know until I ask. Would such an IC (if the concept even exists) need to be programmed, or would the transistor 'functionality' already be in it? Does the question even make sense?

You're not using them on breadboards... I can tell.
Transistors are as good as the description from their datasheets.. trust me.

 

[Reloadron]

I don't mind trannies - I'm a very live-and-let-live kinda guy - but transistors I can't stand.

Don't be so hard on the little guys. How do you think we got where we are today?

The CK722 holds a unique place in the history of the transistor. Introduced by Raytheon in early 1953, the CK722 was the first low cost junction transistor available to the general public. It was an instant success. Countless “build it yourself” articles were published in the popular electronics press and electronics/hobbyist magazines describing how to use the CK722 to build all types of devices such as radios, oscillators, electronic voltmeters, photoelectric alarms and hearing aids. Eager to learn about the exciting new transistor technology, the public responded enthusiastically to the CK722 - hundreds of thousands of these transistors were bought by experimenters, radio hams, engineers and others interested in this technology over the next few years. In addition, there is a sentimental aspect to this device. Many of the talented and dedicated professionals and amateurs who have been responsible for the tremendous rise of the electronics industry over the past four decades can still remember the time when, as a young hobbyist, they were able to scrape together enough money (maybe through saving allowance or cutting the neighbor’s grass) to buy that first CK722 - can you still recall the smell of solder and the absolute delight of hearing a local radio station coming through “loud and clear” on the newly constructed one transistor radio powered by, of course, a gleaming, bright blue CK722? This webpage and book have been constructed to help preserve the special legacy of the Raytheon CK722.

Taken from here.

Just think it was those little guys that led to what we have today and believe me in their day they sure beat the heck out of vacuum tubes to work with for low power entertaining circuits. Oh yeah, valves for those across the pond.

Ron

 

[Hippogriff]

So... I understand you guys all love transistors and want to persuade me to 'get with the programme'... but can I also assume that there is no IC that works like a prepackaged set of transistors? I mean... must I grow to love them too? Or, at the very least, grow to live with them as no IC solution exists?

 

[BrownOut]

I"m sure I've seen transistor arrays packed in DIP packages. But I can't tell you the part number of where to find them.

Otherwise, you can buy dip sockets that mount components and pay some cash strapped kid to soldier the transistors on them.

 

[ericgibbs]

I"m sure I've seen transistor arrays packed in DIP packages. But I can't tell you the part number of where to find them.

Otherwise, you can buy dip sockets that mount components and pay some cash strapped kid to soldier the transistors on them.

hi D,
These are some package transistor arrays.
From what the OP is saying the ULN series would be better for him, ULN2803 for example.

NPN Transistor Arrays - Datasheets, Search, Parameters

Regards

EDIT:
https://uk.farnell.com/jsp/search/b...ions=false&ref=globalsearch&_requestid=951225

 

[vne147]

This one comes in a package of three.

**broken link removed**

 

[ericgibbs]

This one comes in a package of three.

**broken link removed**

I dont fancy yours...

I prefer a surface mount package.!!!!!!

 

[vne147]

I dont fancy yours...

I prefer a surface mount package.!!!!!!

I'll have to search a little harder for those!!!

 

[Hippogriff]

EDIT:
Browse for Products | Farnell United Kingdom

Cool. I took a look at this... CA3083Z... and see something quite big (16 pin) but can be five transistors (5 x 3 = 15 I guess) - looks like it doesn't need power of its own, which is also cool. The only thing I worried about was the current rating - 100mA - when the RGB LED strip is on full white it can be up at 800mA or more, so I'm guessing that's > 200mA per transistor, so this specific device would be out? Or is that necessarily the case?

A 10-pin 3 transistor package with, I suppose, higher current rating would be better... but at least I'm looking at stuff that actually exists now, rather than thinking I'm dreaming about something that might exist.

Going to look at ULN2803 now...

 

[Hippogriff]

This one comes in a package of three.

**broken link removed**

While I like the bright colours on this three-pack, the colours should be coming from my RGB LED.

 

[georgetwo]

hay its like we are in the same boat, all can i do with transistors is switching. i DONT get good result when using it as an amplefier. the world is becoming so advanced that every thing shuld be ic's

 

[Hippogriff]

The ULN2803A looks really cool. But much more complicated than the CA3083Z. Does all this COM and GND stuff mean it requires extra connections? However, it also seems that it has 2.7KΩ resistors going into each transistor Base, currently I use a 470Ω resistor coming out from the PIC output pin into the BC337 Base.

Does that mean I could connect PIC 12F683 output pins directly to ULN2803A Base pins and, in one fell swoop, I would have removed 3 transistors and 3 resistors from my circuit?

I mean, that would be quite snazzy, wouldn't it? Or am I barking up the wrong tree, it says "The ULN2803A has a 2.7-kΩ series base resistor for each Darlington pair for operation directly with TTL or 5-V CMOS devices."

I wonder if there's something that is even closer to a 470Ω resistor and BC337 transistor (x3) in an IC package that can handle higher current than 100mA.

 

[crutschow]

If you have a problem soldering to the transistor leads, then use transistor sockets. Also makes it simple to replace the transistor if it fails.

 

[ericgibbs]

The ULN2803A looks really cool. But much more complicated than the CA3083Z. Does all this COM and GND stuff mean it requires extra connections? However, it also seems that it has 2.7KΩ resistors going into each transistor Base, currently I use a 470Ω resistor coming out from the PIC output pin into the BC337 Base.

Does that mean I could connect PIC 12F683 output pins directly to ULN2803A Base pins and, in one fell swoop, I would have removed 3 transistors and 3 resistors from my circuit?

I mean, that would be quite snazzy, wouldn't it? Or am I barking up the wrong tree, it says "The ULN2803A has a 2.7-kΩ series base resistor for each Darlington pair for operation directly with TTL or 5-V CMOS devices."

I wonder if there's something that is even closer to a 470Ω resistor and BC337 transistor (x3) in an IC package that can handle higher current than 100mA.

hi,
It is possible to parallel the ULN2803 pins in order to increase the current, providing you stay with the TOTAL power dissipation of the package.

 

[vne147]

While I like the bright colours on this three-pack, the colours should be coming from my RGB LED.

Understood. I just felt like inserting a little humor in the thread. In all seriousness though, I would like to echo the sentiment of a few earlier posters and just say that trannies are great! The sooner you become comfortable using individual transistors, the easier a lot of your projects will become. I understand your desire for an interim solutoin while your skills improve but I'd encourage you to try using single transistos again from time to time. You don't want to become overly used to and ultimately dependent on using a more bulky and expensive component than what is necessary for a given project. Just my opinion. Good luck!

 

[Hippogriff]

Transistors always look ugly too, though, I feel. Having two ICs connected - my PIC and something like what we're talking about here - seems that it will be a) neater, b) simpler and c) require less effort (still gotta solder some pins, I understand that). I just don't want to overkill it... as I say, a small package with 3 transistors would be nice. I'll continue searching for what I think the right candidate is and then see if you guys concur.

The CA3083Z looks really straightforward, but I don't think it can handle enough current.

The ULN2803A looks somewhat more complicated but has those inbuilt resistors and can handle the higher current.

If I'm reading things correctly.

The bulky point you make is understood though...